William j



Varten tstrs @stmt fitta IMPROVEMENT 1N SLIDE VALVES,

SPEOIFICAT'ION.

T0 ALL WHOM IT MAY CONCERN: p

Be it knownrthatI, WILLIAM J. STEVENS, of the city, county, and State ofNew York, have invented a new and improved balance Slide Valve; and I dohereby declare that the following is 'a full, clear; and exact'description thereof, reference being had to the accompanying drawing,forming part of this specification, in whichl Figure 1 represents atransverse vertical section of this invention, the line x dig. 2,indicating the piane ofsection. i i l,

Figure 2 is a longitudinal Vertical section of the same, taken on theplane of the line yy, iig. 1.

Similar letters of reference indicate corresponding parts.

This invention consists in the arrangement of a slotted yoke, which issuspended from the flexible top of a cylindrical case rising from thetop of the steam chest, lin combination with a roller tted to travel inthe slotted yoke, and which is secured to the back of the valve in suchmanner that by adjusting the yoke up or down the pressure of the steamon the back of the valve can be counteracted; and it also consists inproviding the said cylindrical case witha flexible or yieldingdiaphragmor top, by which Vthe downward pressure of-the steam` on the valve canbe balanced by the upward pressure en said diaphragm. A. valve is `thusobtained which works just as free and easy under a pressure of a hundredor more pounds to the square inch as it does under the ordinaryatmospheric pressure. I

A represents a slide Valve of any suitable form on shape, and made tofit steam tight on `its seat B. From the back of the valve there risetwo lugs, a, which straddle a slotted yoke, C, and form the bearings'for the axle of a roller b. This roller travels in the slot of theyoke, as shown in iig. 1; and it will be readily understood, from saidfigure, that by adjusting the yoke up or down the pressure of the slidevalve on its seat can be cpuntera'cted, and the slide Valve can be madeto work free and easy, independent of the pressure of the steam to whichit may be exposed. The slotted yoke C is suspended from a flexible oryielding diaphragm D, which forms the top of a cylindrical case E, whichrises from the steam chest cover, and said yoke may be made adjustableby suitable nuts, o1'` in any other desirable manner. The area-of thediaphragm D is so `adjusted that is, the area is of' such extent, thatthe upward pressure .of the steam on its inner surface will balance thedownward pressure of the steam on the back of the valve; therefore, avalve is obtained which is self-balancing, and which, when onceadjusted, requires no further attention, The slotted yoke C is providedwith stops f, which will'strike the inner surface of the steam-chestcover, if said yoke rises up too high. The object of these stops is toprevent the valve from jumping oi' itsy seat, and also to save the.exble top D fromv being forced out any further than it properly shouldbe.

What Ii claim as new, and desire to secure lby Letters Patent, is-

1. The arrangement, relatively to each other, of the slotted yoke C,exible diaphragm D, roller b, stop f, and valve A, substantially asshown and described.44

2. The arrangement of the iexible diaphragm D, with the yoke C, androller `b, substantially as specified.

3. `The stops f, in combination with the yoke C, diaphragm D, and valveA, substantially as and for thepurpose set forth. V

` WM. J. STEVENS.

Witnesses: l

M. M. LIVINGSTON, JonN R. COOPER.

